Emergency cut-off and pressure-maintenance valve for air-brake systems.



J. R. SNYDER. EMERGENCY GUT-OFF AND PRESSURE MAINTENANCE VALVE FOR AIR BRAKE SYSTEMS. APPLIOATIONFILED JUNE 24, 1912.

1 094 944 Patented Apr 28, 1914.

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' UNITED STATES PATENT OFFICE.

JACOB RUSH SNYDER, OF PITTSBURGH, lPENNSYLVANIA, ASSIGNOR TO PERCY E. BONNER, OF PITTSBURGH, PENNSYLVANIA.

Specification of Letters Patent.

Patented Apr. 28, 1914.

Application filed June 24, 1912. Serial No. 705,566.

To all whom it may con cern Be it known that I, J AOOB RUSH SNYDER, a resident of Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Emergency Cut Off and Pressure Maintenance Valves for Air-Brake Systems, of which the following is a specification.

This invention relates to a valve for use in an air brake system and which servesto maintain the train pipe pressure against losses from leakage, which allows for a graduated release of the brakes, and which serves to cut off the steam supply to the engine cylinders and close communication between the main reservoir and the train pipe when the train line bursts from any cause, thereby conserving the main reservoir pressure and also preventing the engine from tearing from the train whenever a hose bursts or any other part of the train line becomes ruptured, or when the conductors valve is opened, and which nevertheless does not 1nterfere with the regular emergency applications of the brakes.

The invention comprises a valve constructed and arranged as hereinafter described and claimed.

In the accompanying drawings Figure 1 is a longitudinal section through the valve; Figs. 2, 3 and i are transverse sections taken respectively on the lines 2-2, 3 3 and 4.-4:, Fig. 1; and Figs. 5, 6 and 7 are diagrammatic horizontal sectional views on the line 5-5, Fig. 1, illustrating the slide valve and valve seat and showing the slide valve in its different positions.

The valve comprises a suitable casing shown as formed in two parts marked re spectively 1 and 2 and suitably joined, such as by means of bolts 3. This casing is provided with a connection 4 leading to the usual engineers brake valve, another connection 5 leading to the train pipe, a connection 6 to the equalizing reservoir, a connection 7 to the main reservoir, and a connection 8 leading to the steam cut-ofi valve,

that is, a valve so arrangedthat upon the admission of compressed air thereto it cuts ed the supply of steam from the engine cylinders.

Between the engineers brake valve con nection i and the train pipe connection 5 is termed a train pipe port.

a seat 10 for the emergency cut-off valve 11, the-latter seating toward the train pipe and when on its seat closing communication between the main reservoir and the train pipe. Valve 11 is provided with 'a hollow stem 12 which is slidably guided in a suitable cage 13 screwed into the casing member 1, said stem having its free end passing through a follower plate 14: slidable in the cage 13 and held on said stem by means of a nut 15 on the extreme end of the valve stem. A

strong spiral spring 16 is interposed between the bottom of the cage and the follower 14: and normally holds the latter against an internal ring or flange 17 in the cage. Within the hollow piston stem 12 is a lighter spring 19 interposed between the bottom of said stem and a follower block 20 in said stem, the latter having a lost motion connection with said stem by means of pin 21 extending through said follower block and extending into slots 22 in the stem.

In the casing member 2 is a suitable piston chamber 24 for piston 25. Chamber 24: is in communication with the train pipe through a suitable port 26 in casing 1, thereby subjecting the piston 25 on one face to train pipe pressure. On its other face, said piston is subject to equalizing reservoir pressure entering through connection 6 into the valve chamber 30. Piston 2-5 is provided with a stem 31 projecting into valve chamber 30 and operatively connected with slide valve 32 which cooperates with valve seat 33 on the bushing 34.

The valve seat 33 is provided with three ports, to-wit, a port 8 communicating with the steam cut-off valve connection 8, a port 7 communicating with the main reservoir '(JOIIHGCUOH 7, and a port 35 communicating with a circular passage 36 in the bushing, and which in turn communicates through passage 37 cored out in the casing member 2 with the piston chamber 24 on the train pipe side of piston 25, so that port 35 in the valve seat may be The slide valve 32 is provided with a suitable cavity 38 for connecting the ports 8*, 7" and 35, hereinafter described. The piston 25 is provided on its face opposite to the valve stem 31 with an annular projection 40 arranged when said piston is moved to the left to contact soon as the train with the follower 14, and with a stem 41 located cent-rally of the annular projection 40 and extending into the hollow valve stem 12 and arranged when the piston moves to the left to contact with follower block in said valve stem.

The cavity 38 of slide valve 32 is arranged in one position to establish communication between main reservoir port 7 and train pipe port 35 and in another position to establish communication between main reservoir port 7 and steam cut-oft valve port 8. The normal position of the valve is shown in Figs. 1, 2, 3, 4 and 5 with the piston in the right hand position holding slide valve 32 in such position as to blank all ports in seat 33, and with the spring 16 holding the cut-off valve 11 in open position, and with the piston 25 subject on one face to equalizing reservoir pressure and on its opposite face to train pipe pressure, which pressures are equal so that said piston and valve remain in the position shown irrespective of whether the system is in running or application condition,-that is to say, the train pipe and equalizing reservoir pressures are equal both when the system is in'running position and also when in application posi* tion.

Should the pressure in the train pipe fall dueto leakage, or like cause which does not produce an abnormally large drop of pres sure, thepressure on piston 25 will then be greater on the equalizing reservoir side. and said piston moves over to the left until its projection 40 contacts with follower plate 14, when the spring 16 arrests further movement in that direction. This brings the slide valve to the position shown in Fig. 6 with the cavity 42 connecting main reservoir port 7 with train pipe port 35 so that main reservoir air can then flow through cavity 38, port 35, passages 36 and 37 to chamber 24, and then to the train pipe, thereby automatically replenishing the train pipe pressure and restoring it to the pressure of the equalizing reservoir. As pipe pressure is slightly in excess of equalizing reservoir pressure. the piston 25 moves in the opposite direc tion, thereby breaking communication between the main reservoir and the train pipe. Should the train pipe again leak, this operation is repeated, so that the valve automatically maintains train pipe pressure against leakage. Should, however, a hose burst, or other sudden rupture of the train line occur, the'e'xcessive drop of pressure on the train pipe side of piston 25 allows said piston to be fully moved over to the left and seal against gaskets43 and 44. The projection contacts with the follower 14: and compresses spring' 16, and positively closes cutoff valve 11' against-seat 10, thereby interrupting communication from the engineers brake valve to the train 7 depletion of the main reservoir pressure which would otherwise occur if the engineers brake alve is in running position. and making it unnecessary for the engineer to move his valve to lap position to conserve main reservoir pressure but leaving him free to perform such other operations as are necessary whenever a hose bursts or in like emergency. At the same time, the slide valve is moved over to the position shown in Fig. 7, so that the cavity 38 now connects main, reservoir port 7 with steam cut-oil valve port 8, thereby permitting main reservoir pressure to flow to the steam cutoff valve and cut off the supply of steam to the engine cylinders. As a consequence. the danger of tearing the engine from the rest of the train whenever a hose bursts is largely avoided, and the waste of main reservoir air is also prevented. The emergency cut-off valve 11, however, does not prevent the application of. the brakes in the usual emergency application. \Vhen such application is required to be made, the necessary reduction of pressure made at the engineers brake valve and the equalizing reservoir is also usually exhausted, so that the air escapes from the train pipe not only at the engineers valve but also at the equalizing valve. Consequently, the pressure on the two sides of piston remains equal and the valve does not act. Even should the equalizing reservoir pressure not be exhausted so that the piston would go over fully to the left, the same as when a hose bursts, it will not interfere with the proper emergency application of the brakes for the reason that the train pipe n'cssure then rushing to the engineers valve will open valve 11 against the relatively light spring 19 and permit the train pipe to be exhausted to the necessary degree.

The valve 11 is provided with an equalizing port 45 for the purpose of enabling the piston 25 to be moved to its normal position after an actuation through the bursting of a. hose. In the train line adjacent to the connection 5 will be placed a shut-oil" cock which will be temporarily closed after an emergency actuation of the valve, and main reservoir pressure will leak through port 45 into the chamber 5 until the pressures on opposite sides of the valve 11 balance, thus permitting spring 16 to move piston 25 to the right. The piston 25 and slide valve 32 also serve to graduate oil the release of the brakes, which is done by the engineer increasing the pressure in the equalizing reservoir to a degree equal to the desired reduction in the brake cylinder pressure. This preponderance of equalizing reservoir pressure over train pipe pressure moves the piston 25 to the left until arrested by projection 4O contacting with follower 14-, so

pipe and preventing that cavity 38 in slide valve 32 establishes communication between the main reservoir port 7 and train pipe port 35 and permits the train pipe pressure to be increased until equal to equalizing reservoir pressure, graduating off the brakes to a corresponding ex tent, as will be readily understood. This provides a very accurate and simple means for graduating off the brakes because the engineer need merely watch his equalizing reservoir gage and admit air to the equalizing reservoir until the gage shows an increase in pressure equal to the amount o't' desired brake cylinder reduction, the valve acting entirely automatically to effect a corresponding increase in train pipe pressure which results in a corresponding decrease in brake cylinder pressure.

The valve described acts entirely automatically, so that upon leakage from the train pipe the pressure is automatically restored, and in case of bursting of the train pipe from any cause the steam is cut oil from the engine cylinders and communication closed between the main reservoir and the train pipe, thereby conserving the main reservoir pressure.

What I claim is:

1. An air brake valve comprising a casing having connections to a steam cut-oil valve, a source of pressure, the main reservoir and the train pipe, a movable abutment in said casing open on one side to train pipe pressure and on its opposite side to reservoir pressure, a valve actuated by said movable abutment, ports and passages controlled by said valve and arranged on reduction of pressure on the train pipe side of the movable abutment to connect the source of pressure with the steam cut-off valve, and a second valve actuated by said movable abutment and acting to cut off communication between the main reservoir and the train pipe.

2. An air brake valve comprising a casing having connections to a steam cut-ofi' valve, a source of pressure, the main reservoir and the train pipe, a movable abutment in said casing open on one side to train pipe pressure and on its opposite side to reservoir pressure, a valve actuated by said movable abutment, ports and passages controlled by said valve and arranged on reduction of pressure on the train pipe side of the movable abutment to connect the source of pressure with the steam cut-ott valve, and a second valve actuated by said movable abutment and acting to cut off communication between the main reservoir and the train pipe, said second valve seating toward the train pipe and having a yielding connection with the movable abutment so as to open under preponderance of train pipe pressure.

3. An air brake valve comprising a casing having connections to a steam cut-ofi' valve,

a source of pressure, the main reservoir and the train pipe, a movable abutment in said casing open 011 one side to train pipe pres sure and on its opposite side to reservoir pressure, a valve actuated by said movable abutment, ports and passages controlled by said valve and arranged on reduction of pressure on the train pipe side of the movable abutment to connect the source of pressure with the steam cut-oft valve, a second valve actuated by said movable abutmentand acting to cut off communication between the main reservoir and the train pipe, and a spring arranged to actuate said last named valve to open communication between the main reservoir and the train pipe.

4. An air brake valve comprising a casing having connections to the main reservoir, a supplementary reservoir, and the train pipe, a movable abutment in said casing subject on one side to train pipe pressure and on its opposite side to supplementary reservoir pressure, a valve actuated by said movable abutment and arranged on moderate preponderance of supplementary reservoir pressure over train pipe pressure to open com- 'mu111cat1o-n from the main reservoir to the train pipe, and a second valve actuated by said movable abutment and arranged on a greater preponderance of supplementary reservoir pressure over train pipe pressure to cut off communication between the main reservoir and the train pipe.

5. An air brake valve comprising a casing having connections to the main reservoir,

the equalizing reservoir, the train pipe and a steam cut-oft valve, a movable abutment in said casing subject on one side to train pipe pressure and on its opposite side to equalizing reservoir pressure, a valve actuated by said movable abutment and arranged on moderate preponderance of equalizing reservoir pressure over train pipe pressure to open communication from the main reservoir to the train pipe and on a greater preponderance of equalizing reservoir pressure over train pipe pressure to open communication from the main reservoir to the steam cut-ofl' valve.

6. An air brake valve comprising a casing having connections to a source of pres sure, a train pipe, a steam cut-oft valve and a reservoir, a movable abutment in said casing open on one side to train pipe pres sure and on its opposite side to reservoir pressure, a valve actuated by said movable abutment, and ports and passages controlled by said valve and arranged on moderate reduction of pressure on the train pipe side of said movable abutment to connect said source of pressure with the train pipe, and on a large reduction of pressure on the train pipe side of the movable abutment to connect a source of pressure with the steam cutoff valve.

. the equalizing reservoir, the

7. An air brake valve comprising a casing having connections to the main reservoir, the equalizing reservoir, the train pipe and a steam cut-off valve, a movable abutment in, said casing subject on one side to train pipe pressure and on its opposite, side to equalizing reservoir pressure, a valve actuated by said movable abutment and arranged on moderate preponderance of equalizing reservo1r pressure over tram pipe pressure to open communication from the main reservoir to the train pipe and on a greater preponderance of equalizing reservoir pressure over train pipe pressure to open communication from the main reservoir to the steam out-0H valve, and a second valve actuated by said movable abutment and arranged on the greater preponderance of equalizing reservoir pressure 0 over train pipe pressure to cut off communisure to open communication from the main reservoir to the steam cut-oft valve, and a second valve actuated by sald movable abutment and arranged on the greater preponderance of equalizing reservoir pressure over train pipe pressure to cut off communication between the main reservoir and the train pipe, said second valve seating toward the train pipe and having a yielding connection with the movable abutment so as to open under preponderance of train pipe pressure.

9. An air brake valve comprising a casing having connections to the main reservoir. the equalizing reservoir, the train pipe and a steam cut-ofl' valve, a movable abutment in said casing subject on one side to train pipe pressure and on its opposite side to equalizing reservoir pressure, a valve actuated by said movable abutment and arranged-on moderate preponderance of equalizing reservoir pressure over train pipe pressure to open communication from the main reservoir to the train pipe and on a greater preponderance of equalizing reservoir pressure over train pipe pressure to open communication from the main reservoir to the steam cut-oil valve, a second valve actuated by said movable abutment and arranged on the greater preponderance of equalizing reservoir pressure over train pipe pressure to cut otf communication be tween the main reservoir and the train pipe, and a spring normally holding said second named valve open and serving as a graduating stop for said movable abutment.

In testimony whereof, I have hereunto set my hand.

JACOB RUSH SNYDER.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

I Washington, D. 0. 

